U.S. patent number 11,198,453 [Application Number 16/132,952] was granted by the patent office on 2021-12-14 for systems and method for a traction system.
This patent grant is currently assigned to Transportation IP Holdings, LLC. The grantee listed for this patent is Transportation IP Holdings, LLC. Invention is credited to Jennifer Lynn Coyne, Adrian Jerzy Gorski, Brian Douglas Lawry, Matthew John Malone, Jeremy Thomas McGarry, Justin Winston, Bret Dwayne Worden.
United States Patent |
11,198,453 |
Winston , et al. |
December 14, 2021 |
Systems and method for a traction system
Abstract
Examples for a traction system are provided. In one example, the
traction system includes a nozzle coupled to an air source and
configured to be selectively aimed toward a determined portion of a
rail surface of a rail, and a conduit configured to supply
pressurized air from the air source to the nozzle, the nozzle
flexibly coupled thereto. The nozzle is configured for the aim of
the nozzle to be controlled to change its aiming direction in
response to a change in curvature of the rail, whereby a stream of
air from the nozzle impacts the determined portion during movement
of the vehicle through the curvature of the rail.
Inventors: |
Winston; Justin (Hermosa Beach,
CA), Gorski; Adrian Jerzy (Erie, PA), Worden; Bret
Dwayne (Erie, PA), Lawry; Brian Douglas (Murrysville,
PA), Malone; Matthew John (Erie, PA), Coyne; Jennifer
Lynn (Lawrence Park, PA), McGarry; Jeremy Thomas (Erie,
PA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Transportation IP Holdings, LLC |
Norwalk |
CT |
US |
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Assignee: |
Transportation IP Holdings, LLC
(Norwalk, CT)
|
Family
ID: |
58053272 |
Appl.
No.: |
16/132,952 |
Filed: |
September 17, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190054930 A1 |
Feb 21, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15331135 |
Oct 21, 2016 |
10106177 |
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14460502 |
Aug 1, 2017 |
9718480 |
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62245586 |
Oct 23, 2015 |
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61866248 |
Aug 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61C
15/107 (20130101); B61C 17/12 (20130101); B61C
15/08 (20130101) |
Current International
Class: |
B61C
15/08 (20060101); B61C 17/12 (20060101); B61C
15/10 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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103863338 |
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Jun 2014 |
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CN |
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2006000093 |
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Jan 2006 |
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WO |
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2013179159 |
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Dec 2013 |
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WO |
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2017070677 |
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Apr 2017 |
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WO |
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Other References
European Patent Office, Extended European Search Report Issued in
Application No. 16858440.7, dated Jun. 17, 2019, Germany, 73 pages.
cited by applicant .
IP Australia Patent Office, Examination Report Issued in
Application No. 2018232977, dated Sep. 10, 2019, 4 pages. cited by
applicant .
ISA Korean Intellectual Property Office, International Search
Report and Written Opinion Issued in Application No.
PCT/US2016/058483, dated Feb. 1, 2017, WIPO, 12 pages. cited by
applicant .
International Bureau of WIPO, International Preliminary Reporton
Patentability Issued in Application No. PCT/US2016/058483, dated
Apr. 24, 2018, WIPO, 10 pages. cited by applicant .
Australian Intellectual Property Office, Examination Report Issued
in Application No. 2016342439, dated Nov. 30, 2018, 3 pages. cited
by applicant.
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Primary Examiner: Khatib; Rami
Attorney, Agent or Firm: McCoy Russell LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. application Ser. No.
15/331,135 filed Oct. 21, 2016, which claims priority to U.S.
Provisional Application No. 62/245,586, filed Oct. 23, 2015. U.S.
application Ser. No. 15/331,135 is also a continuation-in-part of
U.S. application Ser. No. 14/460,502, filed Aug. 15, 2014, and
issued as U.S. Pat. No. 9,718,480 on Aug. 1, 2017, which claims
priority to U.S. Provisional Application No. 61/866,248, filed Aug.
15, 2013. The entire contents of the above-referenced applications
are hereby incorporated by reference for all purposes.
Claims
The invention claimed is:
1. A traction system for a vehicle, comprising: a nozzle coupled to
an air source and configured to be selectively aimed toward a
surface of a route; a conduit configured to supply pressurized air
from the air source to the nozzle, the nozzle flexibly coupled
thereto; and an actuator that is configured to control the nozzle
to aim at a determined portion of the surface of the route, the
determined portion based on a location of the surface proximate to
a wheel of the vehicle, and to control the nozzle to change its
aiming direction in response to a change in curvature of the route
such that a stream of air from the nozzle impacts the determined
portion during movement of the vehicle through the curvature of the
route; wherein the actuator comprises an electromagnet that is
coupled to the nozzle, and wherein the electromagnet is coupled to
a voltage source and is energized from the voltage source
responsive to a signal from an electronic controller, wherein the
flexible coupling of the nozzle is provided by a lever bracket
mounted to a frame of the vehicle and mounted to the conduit, and
further comprising a resilient member coupled between the lever
bracket and a journal bearing housing of a lead axle of the
vehicle, and wherein the lever bracket transforms lateral movement
of the frame relative to the lead axle in a first direction to
lateral movement of the nozzle in a second, opposite direction, as
the curvature of the rail changes.
2. A traction system for a vehicle, comprising: a nozzle coupled to
an air source and configured to be selectively aimed toward a
determined portion of a rail surface of a rail, and the determined
portion is based on a location of the rail surface between edges of
the rail and proximate to a wheel of the vehicle; and a conduit
configured to supply pressurized air from the air source to the
nozzle, the nozzle flexibly coupled thereto; wherein the nozzle is
configured for the aim of the nozzle to be controlled to change its
aiming direction in response to a change in curvature of the rail
such that a stream of air from the nozzle impacts the determined
portion during movement of the vehicle through the curvature of the
rail, wherein the flexible coupling of the nozzle is provided by a
lever bracket mounted to a frame of the vehicle and mounted to the
conduit, and further comprising a resilient member coupled between
the lever bracket and a journal bearing housing of a lead axle of
the vehicle, and wherein the lever bracket transforms lateral
movement of the frame relative to the lead axle in a first
direction to lateral movement of the nozzle in a second, opposite
direction, as the curvature of the rail changes.
3. The traction system of claim 2, further comprising an actuator
that is configured to force the nozzle aiming direction in response
to the change in the curvature of the rail.
4. The traction system of claim 3, wherein the actuator comprises
an electromagnet that is coupled to the nozzle.
5. The traction system of claim 4, wherein the electromagnet is
coupled to a voltage source and is energized from the voltage
source responsive to a signal from an electronic controller.
6. The traction system of claim 2, further comprising a sensor
configured to track the rail for curvature and an actuator
configured to actuate the nozzle to change the aiming direction to
maintain the impact of the air stream on the rail portion during a
curve.
7. The traction system of claim 2, wherein the nozzle is positioned
to point at a location in front of a lead wheel of the vehicle,
such that the nozzle is configured to direct a stream of
pressurized air to a point on the rail proximate where the lead
wheel contacts the rail.
8. The traction system of claim 2, wherein the conduit is coupled
to a journal bearing housing of a lead axle of the vehicle.
9. The traction system of claim 2, wherein the air source is
configured to provide air at a pressure of greater than 620 kPa
sufficient to provide the air stream at a velocity of greater than
23 meters per second sufficient to increase the tractive effort of
the wheel on the rail.
Description
BACKGROUND
Technical Field
Embodiments of the subject matter disclosed herein relate to
tractive effort for a plurality of wheels of a vehicle, for
example.
Discussion of Art
Rail vehicles, such as locomotives, have a plurality of wheels
configured to move along a rail, or track. Rail vehicles may pull
large loads, such as multiple loaded rail cars, over long lengths
of tracks. To operate efficiently, the rail vehicle is typically
operated with a maximum of tractive effort. However, tractive
effort is limited by the amount of contact friction between the
wheels of the rail vehicle and the patch of rail over which the
wheels are passing at any given moment. This amount of friction, in
turn, depends such factors as the presence of contaminants (snow or
ice, oil, mud, soil, etc.) on the rail or wheel, the shape
(roundness) of the wheel, the shape of the rail, atmospheric
temperature, humidity, and the normal force or weight imposed on an
axle, among others.
BRIEF DESCRIPTION
In an embodiment, a traction system for a vehicle includes a nozzle
coupled to an air source and configured to be selectively aimed
toward a determined portion of a rail surface of a rail, and the
determined portion is based on a location of the rail surface
between edges of the rail and proximate to a wheel of the vehicle.
The traction system further includes a conduit configured to supply
pressurized air from the air source to the nozzle, the nozzle
flexibly coupled thereto. The nozzle is configured for the aim of
the nozzle to be controlled to change its aiming direction in
response to a change in curvature of the rail, whereby a stream of
air from the nozzle impacts the determined portion during movement
of the vehicle through the curvature of the rail.
In an embodiment, a control system, e.g., a system for controlling
a consist of rail vehicles or other vehicles, includes a control
unit electrically coupled to a first rail vehicle in the consist.
The control unit has a processor and is configured to receive
signals representing a respective presence and position of one or
more tractive effort systems on-board the first vehicle and other
rail vehicles in the consist. The system further includes a set of
instructions stored in a non-transient medium accessible by the
processor. The instructions are configured to control the processor
to create a schedule (e.g., an optimization schedule) that manages
the use of the one or more tractive effort systems based on the
presence and position of the tractive effort systems within the
consist.
In an embodiment, a method for controlling a consist of at least
first and second rail vehicles or other vehicles includes the steps
of determining a configuration of tractive effort systems within
the consist and enabling the tractive effort systems in dependence
upon the determined configuration to increase tractive effort.
In an embodiment, a method for controlling a flow of air to a
tractive effort system of a rail vehicle or other vehicle includes
the steps of providing a supply of pressurized air from a reservoir
to the tractive effort system, and varying the flow of air to the
tractive effort system to maintain a pressure in the reservoir
above a predetermined lower threshold.
In an embodiment, a system for control of a rail vehicle or other
vehicle includes a tractive effort device having a nozzle
positioned to direct a flow of air to a rail, a reservoir fluidly
coupled to the tractive effort device for providing a supply of
compressed air to the tractive effort device, and a control unit
electrically coupled to the tractive effort device and configured
to control a flow of compressed air from the reservoir to the
tractive effort device in dependence upon an available pressure
within the reservoir.
In an embodiment, a system (for use with a vehicle having a wheel
that travels on a surface, e.g., a rail vehicle having a wheel that
travels on a rail) includes a tractive effort system including an
air source for supplying compressed air and a nozzle fluidly
coupled to the air source and configured to direct a flow of
compressed air from the air source to a contact surface of the
rail, and a control unit electrically coupled to the tractive
effort system and configured to control the tractive effort system
between an enabled state, in which compressed air flows from the
air source and out of the nozzle of the tractive effort system, and
a disabled state, in which compressed air is prevented from exiting
the nozzle. The control unit is further configured to control the
tractive effort system from the enabled state to the disabled state
in dependence upon the presence of at least one adverse
condition.
In an embodiment, a method for controlling a rail vehicle or other
vehicle includes providing a tractive effort system having a nozzle
for directing the flow of compressed air to the contact surface of
a rail and disabling the tractive effort system when an adverse
condition is detected.
In an embodiment, a system (for use with a vehicle having a wheel
that travels on a surface, e.g., a rail vehicle having a wheel that
travels on a rail) includes an air source for supplying compressed
air, a nozzle fluidly coupled to the air source and configured to
direct a flow of compressed air from the air source to a contact
surface of the rail, and a valve positioned intermediate the air
source and the nozzle. The valve is controllable between a first
state in which the compressed air flows from the air source to the
nozzle, and a second, disabled state in which the compressed air is
prevented from flowing to the nozzle. The system further includes a
controller for controlling the valve between the first state and
the second, disabled state, and an operator interface electrically
coupled to the controller. The operator interface includes a
momentary disable switch biased to a position that controls the
valve to the first state and movable against the bias to control
the valve to the second, disabled state.
In an embodiment, a system (for controlling a consist of vehicles
having a plurality of wheels that travel on a surface, e.g., a
consist of rail vehicles having a plurality of wheels that travel
on a rail) includes a tractive effort system on-board a first rail
vehicle. The tractive effort system includes a media reservoir
capable of holding a tractive material, a tractive material nozzle
in communication with the media reservoir and configured to direct
a flow of tractive material to a contact surface of the rail, a
compressed air reservoir, and a compressed air nozzle in
communication with the compressed air reservoir and configured to
direct a flow of compressed air to the contact surface of the rail.
The system further includes a control unit electrically coupled to
a first rail vehicle in the consist, the control unit having a
processor and being configured to receive signals indicative of
slippage, individual axle tractive effort, overall rail vehicle
tractive effort and horsepower. The control unit is further
configured to control the tractive effort system to apply
compressed air only to the contact surface of the rail and monitor
at least one of slippage, individual axle tractive effort, overall
rail vehicle tractive effort and horsepower after application of
the compressed air only.
In an embodiment, a method for controlling a rail vehicle or other
vehicle having a tractive effort system includes the steps of
enabling the tractive effort system to apply a blast of air only to
the rail, monitoring one of slip, individual axle tractive effort,
overall tractive effort and horsepower, and enabling the tractive
effort system to apply tractive material to the rail in dependence
upon at least one parameter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows a schematic diagram of a rail vehicle with three
motor combos according to an embodiment of the invention.
FIG. 1B shows a schematic diagram of one motor combo of FIG.
1A.
FIG. 2-6 schematically illustrate embodiments of a traction system
having a resiliently-mounted nozzle.
FIG. 7 is a flow chart illustrating a method for operating a
traction system according to an embodiment of the invention.
FIG. 8 is a schematic drawing of an exemplary rail vehicle.
FIG. 9 is a schematic drawing of a rail vehicle consist, according
to an embodiment of the present invention.
FIG. 10 is a flow diagram of a compressed air system of a rail
vehicle, according to an embodiment of the present invention.
FIG. 11 is a schematic drawing of a tractive effort system on a
rail vehicle, according to an embodiment of the present
invention.
FIG. 12 is a schematic drawing of a tractive effort system equipped
rail vehicle consist, according to an embodiment of the present
invention.
FIG. 13 is a flow diagram illustrating a method for estimating the
air flow delivered to an MRE trainline, according to an embodiment
of the present invention.
FIG. 14 is schematic drawing of a variable flow tractive effort
system, according to an embodiment of the present invention.
FIG. 15 is a schematic diagram of a variable flow tractive effort
system, according to another embodiment of the present
invention.
FIG. 16 is a block diagram illustrating the implementation of a
smart-disable control strategy for a noise-sensitive area,
according to an embodiment of the present invention.
FIG. 17 is a block diagram illustrating the implementation of a
smart-disable control strategy for a tractive effort system having
minimal positive impact, according to an embodiment of the present
invention.
FIG. 18 is a block diagram illustrating the implementation of a
smart-disable control strategy based on GPS heading information,
according to an embodiment of the present invention.
FIG. 19 is a block diagram illustrating the implementation of a
smart-disable control strategy based on GPS location information,
according to an embodiment of the present invention.
FIG. 20 is a block diagram illustrating the implementation of a
smart-disable control strategy based on tractive effort system
effectiveness, according to an embodiment of the present
invention.
FIG. 21 is a schematic drawing of a tractive effort system having
an operator interface, according to an embodiment of the present
invention.
FIG. 22 is a state machine diagram illustrating the response of a
tractive effort control system to operator inputs, according to an
embodiment of the present invention.
FIG. 23 is a graph FIG. 23 illustrating tractive effort threshold
as a function of locomotive speed.
FIG. 24 is a state machine diagram illustrating a sand reduction
control strategy for a tractive effort system, according to an
embodiment of the present invention.
FIG. 25 is a state machine diagram illustrating another sand
reduction control strategy for a tractive effort system, according
to an embodiment of the present invention.
FIG. 26 is a state machine diagram illustrating another sand
reduction control strategy for a tractive effort system, according
to an embodiment of the present invention.
FIG. 27 is a block diagram illustrating a method for detecting
clogs in a tractive effort system, according to an embodiment of
the present invention.
FIG. 28 is a state machine diagram illustrating a method for
detecting the change in non-tractive effort system air flow,
according to an embodiment of the present invention.
FIG. 29 is a flow diagram illustrating a method for estimating air
compressor and tractive effort system flow, according to an
embodiment of the present invention.
FIG. 30 is a state machine diagram illustrating a method for
detecting clogs in a tractive effort system, in accordance with an
embodiment of the present invention.
FIG. 31 is a state machine diagram illustrating a method for
detecting leaks in a tractive effort system, in accordance with an
embodiment of the present invention.
FIG. 32 is a state machine diagram illustrating a method for
determining the effectiveness of a tractive effort system, in
accordance with an embodiment of the present invention.
FIG. 33 is a state machine diagram illustrating a tractive effort
system control strategy based upon a determined tractive effort
system effectiveness, according to an embodiment of the present
invention.
DETAILED DESCRIPTION
Embodiments are disclosed herein that relate to a traction system
for a vehicle, where the traction system modifies the traction of a
wheel contacting a surface. In one example, the vehicle may be a
rail vehicle, such as a locomotive, and the surface may be a
surface of a rail. In another example, the vehicle may be an
on-road vehicle such as an automobile, and the surface may be a
surface of a road. The traction system may include a nozzle coupled
to an air source. The air source may be a compressed air tank or
other suitable supply of pressurized or compressed air. The nozzle
may be configured to be selectively aimed toward a determined
portion of the surface. The determined portion may be a location of
the surface between edges of the surface (e.g., between an inner
surface and an outer surface of a rail) and proximate to a wheel of
the vehicle. The traction system further includes a flexible
coupling (e.g., a conduit) between the nozzle and the air source,
such as a pipe, tube, or hose. The nozzle is controlled to change
its aiming direction in response to a change in curvature of the
surface, and a stream of air form the nozzle impacts the determined
portion of the surface during movement of the vehicle through the
curvature of the surface.
In this way, the traction system may provide a stream of air that
impacts the surface on which the vehicle is traveling at a
determined location of the surface during vehicle movement. The
stream of air may be at sufficient velocity to dislodge water, ice,
or other debris from the surface to increase traction. The traction
system includes a moveable nozzle that may be actuated to change
its aiming direction to maintain the impact of the air stream on
the determined location when the vehicle is traveling over a curved
portion of the surface. As used herein, the terms "air stream" and
"stream of air" may refer to a supply of air from the traction
system to a surface that only includes air and does not include any
additional added constituents such as sand or other abrasives.
However, in some examples, the tractions system may include a
separate sander to supply abrasives to the surface, while in other
examples abrasives may be supplied along with the air stream.
The approach described herein may be employed in a variety of
mobile platforms, such as engine-driven vehicles,
electrically-driven vehicles, or vehicles propelled according to
another suitable mechanism. Such vehicles can include on-road
transportation vehicles, as well as mining equipment, marine
vessels, rail vehicles, and other off-highway vehicles (OHV). For
clarity of illustration, a locomotive is provided as an example of
a self-propelled rail vehicle, and more broadly, as an example of a
mobile platform, supporting a system incorporating an embodiment of
the invention.
FIG. 1A is a block diagram of a locomotive or other rail vehicle
100 according to an embodiment of the invention. The locomotive or
other rail vehicle 100 shown in FIG. 1A comprises a superstructure
102 and a rail vehicle truck 106. The superstructure 102 may be the
body of the locomotive or other rail vehicle 100. The rail vehicle
truck 106 may include a frame and motor combos 112 mounted thereto
that transport the locomotive or other rail vehicle 100 along rails
101. As shown, the rail vehicle includes three motor combos.
The rail vehicle 100 may include an engine (not shown), such as an
internal combustion engine, which may be mechanically coupled to an
alternator. For example, the engine may be a diesel engine that
generates a torque output that is transmitted to the alternator.
The alternator produces electrical power that may be stored and
applied for subsequent propagation to a variety of downstream
electrical components. As an example, the alternator may be
electrically coupled to a plurality of traction motors (described
below) and may provide electrical power to the plurality of
traction motors. In some examples, the plurality of traction motors
may be powered by an alternate source, such as via an on-board
battery or fuel cell, overhead electric wires, etc.
FIG. 1B is a schematic diagram of a motor combo according to an
embodiment of the invention. Each motor combo 112 typically
includes two train wheels 114, an axle 116 connecting the wheels
114, two journal bearing housings 118, a bull gear 120, and a
traction motor 122. The journal bearing housing 118 contains a
roller bearing for the axle. In a more general sense, each motor
combo 112 is a device or assembly (disposed or to be disposed in a
rail vehicle truck) that includes a traction motor 122 and some or
all of the equipment (e.g., axle 116, wheels 114) used for
interfacing the motor 122 with the rails on which the vehicle
travels, for moving the vehicle along the rails.
As described above, the tractive effort of the plurality of wheels
is dependent on the amount of friction that is generated between
each wheel and the patch of rail with which the wheel is in
contact. Various factors may affect the amount of friction
generated, including contaminates present on the rail. In
particular, adverse weather conditions may result in snow, ice,
and/or water being present on the rail. Because these conditions
may appear suddenly, and are particularly prone to occurring in
mountainous regions where haulage ability is already limited by
steep grades, rail vehicle operators may choose to avoid
mountainous routes and/or limit the tonnage of the load being
pulled, to avoid loss of traction.
One approach for improving adhesion between the wheels and the rail
during conditions of wheel slip/loss of tractive effort includes
removing contaminates from the rail prior to the wheels contacting
the rail. To achieve this, rail vehicles may be equipped with a
rail cleaning system including a pipe having a nozzle pointed at
the location of the rail where the wheel contacts the rail, just in
front of the lead wheels of the rail vehicle. The nozzle may direct
high-pressure air onto the rail, clearing the rail of snow, water,
dirt, or other debris, thus increasing the friction between the
rail and wheels. The rail cleaning system may direct the air to the
rail upon request from an operator, or automatically in response to
detection of wheel slip, for example.
While such a system may efficiently remove contaminates from the
rail and increase tractive effort of the vehicle, it may encounter
difficulty when the rail vehicle is traversing a curve, if the
cleaning system nozzle has a fixed position relative to the rail
vehicle. When the rail vehicle traverses a curve, the wheels may
move laterally. For example, the wheels may be configured to
contact the rail on the center of the rail while traveling on a
straight rail, and then shift to the left of the rail as the rail
curves to the right and the wheels continue to move in a straight
path. Further, the rail ahead of the wheels has a curvature that
the vehicle is following, but the body of the vehicle may remain
substantially tangent to this curve at any given point in time. As
a result, the nozzle may not point to the rail and may instead
direct air to the side of the rail. Not only does this result in
contaminates not being removed from the rail, but it also can cause
snow, dirt, or other debris to blow onto the rail, further reducing
the friction and tractive effort.
When the nozzle is rigidly mounted, the air flow is directed away
from the desired target area while the rail vehicle traverses a
curve. The high rail airflow shifts towards the outside of rail
while the low rail airflow shifts toward the inside of the rail.
This is due to 1) the lateral shift of the wheel set, 2) the attack
angle between the wheel and the rail, 3) any wheel flange wear (and
rail wear), and 4) any track gauge widening (though this effect is
only experienced at the low rail).
Thus, according to embodiments disclosed herein, a traction system
may be configured so that a nozzle may follow a surface on which
vehicle is traveling as the vehicle traverses a curve. In one
example illustrated in FIG. 2, a traction system 200 may include a
resiliently-mounted nozzle. The traction system 200 includes a
nozzle 208 coupled to an air source via a passage 206 (e.g., a
conduit such as a pipe, hose, tube, or other conduit). The passage
may be coupled to a suitable structure of the vehicle, such as to a
support structure of a lead axle of the vehicle (e.g., to a journal
bearing housing, such as journal bearing housing 118 of FIG.
1B).
As explained above, the nozzle directs the air onto a surface 204
ahead of a wheel 202 of a lead axle. In one example, the surface
may be a surface of a rail (also referred to as a track). In such
examples, the nozzle is configured to be selectively aimed toward a
determined portion of a rail surface. In one example, the
determined portion of the rail surface may be a location of the
rail surface between the edges of the rail and proximate to the
wheel. The determined portion includes a region of the rail surface
where the air stream impacts the rail surface. The determined
portion may comprise a suitable region of the rail surface, such as
near an inner edge of the rail surface, near an outer edge of the
rail surface, or in the center of the rail surface. In some
examples, the determined portion may be a fixed region, while in
other examples the determined portion may change depending on rail
curvature (e.g., when on a straight section of the rail, the
determined portion may be near an outer edge of the rail surface,
while when on a curved section of the rail, the determined portion
may be in a center of the rail surface. The determined
portion/impact area may be a given distance from the wheel (e.g., 5
cm, 10 cm, half a meter, or other suitable distance). The nozzle
may be angled away from the wheel in one example. In some examples,
the nozzle may be angled inward towards the vehicle or angled
outward away from the vehicle.
In other examples, the surface may be a road, and the nozzle may be
configured to be selectively aimed toward a determined portion of
the road surface. The determined portion of the road surface may be
a location of the road surface between edges of the road and
proximate the wheel, and may have similar characteristics as the
determined portion of the rail surface described above (e.g.,
located in front of the wheel by a certain distance, in the center
and/or near an edge of the road surface, etc.).
The passage is configured to supply pressurized air from the air
source to the nozzle. The passage may be flexible (e.g., comprised
of rubber or other flexible material) so that the nozzle can follow
the surface as the wheels shift relative to the surface and/or the
vehicle traverses a curve. Further, the nozzle may be flexibly
coupled to the passage.
The air source may include compressed air, such as from a
compressed air tank of the vehicle, from downstream of intake air
compressor of an engine, or other suitable source of compressed
air. The air source may supply compressed air at a rate of 2.5-5.5
standard cubic meters per minute and/or at a pressure of 90-150 psi
(620-1030 kPa). The nozzle may supply the stream of air to the
surface at a pressure of 90-150 psi (620-1030 kPa) and/or at an
impact velocity of greater than 23 meters per second. In one
example, the air source, passage, and nozzle may be configured to
provide a suitable pressure ratio at the nozzle, in order to supply
the air stream at a desired velocity. For example, the nozzle may
be a convergent-divergent nozzle, and the air source, passage, and
nozzle may be configured to provide a pressure ratio that will
result in sonic or supersonic air stream velocity at the nozzle
exit, such as at a pressure ratio of 1.89 or greater. In one
example, the system may generate pressurized air at greater than
the sonic pressure ratio relative to ambient pressure to provide
choked flow through the nozzle, with only air flowing through the
nozzle and without any sand through the nozzle and without any sand
carried by the airflow passing through and exiting the nozzle en
route to the rail.
The nozzle may include an actuator 210 or other structure that may
change the aiming direction of the nozzle, in response to a change
in a curvature of the surface, for example. In this way, a stream
of air from the nozzle may impact the determined portion of the
surface during movement of the vehicle in which the traction system
is mounted through the curvature of the surface.
The actuator may be a suitable actuator that forces the aiming
direction of the nozzle in response to the change in curvature. In
one example, the actuator is an electromagnet. The electromagnet
may be positioned in a suitable location on the nozzle, for example
the electromagnet may be annular and surround the opening of the
nozzle, or may be positioned in another suitable location. The
electromagnet may be energized from a voltage source 212 responsive
to a signal from an electronic controller 214, for example. Once
energized, the electromagnet may remain in a fixed position
relative to the surface due to the attraction between the magnet
and the steel (or other metal) material of the surface (e.g., the
rail). Because the passage is made from flexible material (e.g.,
rubber), the nozzle is then able to move relative to the truck
frame and wheels. The electronic controller may include
non-transitory instructions stored in memory that when executed
cause the controller to send a signal to activate the
electromagnet, e.g., the controller may activate a switch coupled
between the voltage source and the electromagnet. The instructions
may include instructions to activate the electromagnet when a curve
is detected, when wheel slip is detected, responsive to a user
request, and/or other suitable parameters.
In some examples, the traction system 200 may include one or more
sensors 218 for detecting the curvature of the surface. The one or
more sensors may include optical sensor(s), magnetic sensor(s), or
other suitable sensors that may determine surface curvature by
sensing the shape of the surface itself, or by sensing relative
movement between vehicle components that may shift as the vehicle
traverses a curved portion of the surface. For example, the one or
more sensors may detect linear motion between a truck and an
axle/axle mounted components of the vehicle. In another example,
the one or more sensors may sense the angular motion between the
truck and a car body of the vehicle.
The output from the one or more sensors may be sent to the
controller, and the controller may determine the aiming direction
of the nozzle based on the sensor output. For example, the sensor
output may be used by the controller to determine a curvature of
the surface, and the controller may include a look-up table that
maps nozzle aiming direction to surface curvature. The controller
may obtain the aiming direction by inputting the surface curvature
into the look-up table. The aiming direction may include an amount
of displacement from a default position of the nozzle (e.g., in
length, degrees, or other suitable measurement).
The controller may then send a command to the actuator to activate
the actuator to control the nozzle aiming direction to the
determined aiming direction. In one example, the nozzle may have a
default position where the nozzle is centered over or otherwise
aiming toward the determined portion of the surface, when the
surface is straight. Once the vehicle begins, or is about to begin,
traversing a curve of the surface, the nozzle may be controlled to
change its aiming direction so that it continues to supply air to
the determined location of the surface. After the vehicle has
traversed the surface, the nozzle may be controlled to return back
to the default position, e.g., by ceasing activation/energizing of
the actuator.
As explained above, the actuator may include an electromagnet. In
one example, the amount of energy supplied to the electromagnet may
be based on the determined aiming direction. In another example,
the electromagnet may include a plurality of electromagnets
distributed around the nozzle, for example. In such cases, which
electromagnets are energized may be based on the aiming direction.
For example, if the aiming direction is to the right of the default
position, one or more electromagnets on the right side of the
nozzle may be energized, while if the aiming direction is to the
left of the default position, one or more electromagnets on the
left side of the nozzle may be energized.
In another example, the actuator may be a stepper motor or other
type of motor that moves the nozzle responsive to a command from
the controller. In such an example, an amount of energy supplied to
the motor may be based on the aiming direction, for example the
controller may determine a duty cycle of the motor based on the
aiming direction and operate the motor at the determined duty
cycle.
The nozzle of the traction system may be positioned and controlled
to be aimed away from the wheel in order to ensure the debris is
cleared from the surface before the wheel contacts that portion of
the surface. Additionally, by pointing the nozzle away from the
wheel rather than toward the wheel, space may be made available to
then apply abrasive to the surface, without the high-velocity
stream of air dislodging the abrasive. For example, a sander 220
may be present to supply sand or other abrasives toward the wheel.
The sander may point toward the wheel, while in some examples the
nozzle that supplies air may point away from the wheel. The sander
may not be configured to change aiming direction, as the sander may
spray abrasive in a broad arc that impacts the surface even when
the surface is curved. Further, the sander may spray sand (and any
air used to force the sand out of the sander) at a relatively low
velocity, such as less than 23 meters per second and/or at a
pressure less than 90 psi (620 kPa).
An additional or alternative mechanism to adjust the aiming
direction of the nozzle includes transferring relative motion
between the vehicle frame and wheel set to the nozzle and/or
associated passage. Such a mechanism is described below with
respect to FIGS. 3-6. While FIGS. 3-6 are described with respect to
a vehicle traversing a rail (such as a locomotive), it is to be
understood that a similar mechanism may be employed for other
vehicle types and/or on other surfaces.
As described above, the wheels of the vehicle are configured to
move laterally with respect to the frame of the vehicle as the
vehicle traverses a corner. This lateral displacement may be
utilized to adjust the position of the nozzle and associated
passage so that the nozzle maintains a fixed position relative to
the surface, even as the surface curves. This mechanism utilizes
the inherent relative lateral motion between the wheel set and the
truck frame to deflect the initial orientation of the nozzle
through the use of a resilient mount on the wheel set and
hard-mounted lever bracket on the truck frame. The wheels are fixed
to the axle, but the axle can shift laterally relative to the truck
frame. Lateral play is provided between journal bearing housing and
truck frame.
Three axle trucks utilize lateral axle clearance to help negotiate
tight curves. Normally the clearance between the wheel set and the
rail, sometimes called flange clearance, allows the truck with a
relatively long wheelbase to negotiate through the curve.
Additionally, some rail vehicles may have tapered wheels and this
flange clearance also allows the tapered wheel to move laterally
and thus change its rolling radius, in order to reduce sliding. As
the curvature becomes more severe, this wheel flange clearance is
used up and lateral forces between the track and wheels increase.
To alleviate this, the axles of the truck are allowed move in a
lateral direction, relative to the truck frame and each other.
This motion may be utilized to maintain the nozzle of the traction
system over the rail. As the truck enters any curve, the wheel set
is forced to follow the rail while the truck frame continues on a
tangent path (as shown in FIG. 4). This creates relative lateral
motion between the truck and the wheel set. This motion is
controlled by the amount of the designed clearance between the
truck frame and the wheel set. The nozzle is resiliently mounted on
the journal bearing housing which is mounted on the end of the axle
and follows the position of the wheel. Another bracket is mounted
on the truck frame and acts as a lever which deflects the journal
bearing housing mounted nozzle, as illustrated schematically in
FIGS. 3-6 and described in more detail below.
FIG. 3 schematically shows a first view 300 of the mechanical
coupling between the nozzle and flexibly-coupled passage (e.g., the
pipe, tube, or hose) and a support of a lead axle of the vehicle
(e.g., a journal bearing housing) via a lever bracket. A set of
rails 650 is illustrated with a wheel set coupled to an axle, which
is in turn coupled to two respective journal bearing housings (also
referred to as J-boxes).
A traction/rail cleaning system is schematically shown for each
wheel/rail, including a first traction system 310 and a second
traction system 320. Each of the first traction system 310 and
second traction system 320 may be non-limiting examples of the
traction system 200 described above with respect to FIG. 2. As
such, each traction system includes a nozzle coupled to a pipe that
is mounted to a respective journal bearing housing. Thus, as shown,
the first traction system 310 includes a nozzle 312 coupled to a
pipe 314 mounted to a lever bracket 316. The second traction system
320 includes a nozzle 322 coupled to a pipe 324 mounted to a lever
bracket 306. The wheel/rail contact point for each wheel, which
only comprises a portion of the respective rail (e.g., 1/6.sup.th
of the width of the rail), is shown schematically at 318 and 328,
while the impact point (the position on the rail where the nozzle
of the traction system directs the pressurized air) for each
traction system is schematically shown at 611 and 621. As
illustrated, each impact point is located in front of, and spaced
apart by a threshold distance, the respective wheel/rail contact
point. Because of the separation between the impact point and the
wheel contact location, curvature of the rail may result in the
target impact point changing its position relative to the wheel
contact point, compared to when the rail is straight. For example,
the target impact point and wheel contact location may be aligned
along a straight line that is parallel to the longitudinal axis of
the rail when the rail is straight. When the rail is curved, the
target impact point (e.g., the center of the rail surface) may be
aligned with the wheel contact location along a diagonal line.
Each journal bearing housing is mounted to a lever bracket via a
set of bellows or other resilient member (e.g., spring). Each lever
bracket is coupled to the truck frame. For example, as shown in
FIG. 3, the second traction system is mounted to a lever bracket
306 that is mounted to the truck frame 308 (e.g., a frame of the
truck 106 of FIG. 1A). The lever bracket 306 is coupled to the
journal bearing housing 302 (e.g., journal bearing housing 118 of
FIG. 1B) via a bellows 304. Likewise, the first traction system is
mounted to lever bracket 316, which is mounted to the truck frame
308. The lever bracket 316 is mounted to the journal bearing
housing 303 via a bellows 305.
The frame may include lips or tabs on each side of the lever
bracket that define a flange clearance of the lever bracket. Once
the flange clearance is used up, the leftward lateral movement of
the truck frame shifts the bottom end of the lever bracket to the
left, causing the top end of the lever bracket to shift to the
right, as shown in FIG. 4. The lever bracket is now angled by an
amount that is based on the lateral movement of the truck frame. As
a result, the nozzle is shifted to the right and the impact point
is on the rail, even though the rail is curving to the right.
Accordingly, as shown by a second view 400 of FIG. 4, the
wheel/rail contact points 418 and 428 remain in substantially the
same relative lateral location (e.g., relative to the edges of the
rail) and the impact points 411 and 421 stay centered over the
respective rails.
As described above, the frame of the vehicle may move laterally
during traversal of a curve, and this relative motion may be
transferred to the nozzle to change the aiming direction of the
nozzle in a lateral direction (e.g., left to right). However, the
frame of the vehicle may also move vertically and mechanisms may be
included to translate the vertical motion to the nozzle, for
example to maintain the nozzle at a fixed distance above the rail
surface. For example, the frame 308 may include a lip that
protrudes out along a bottom of the frame that is configured to
engage the lever bracket (e.g., 306) if vertical movement of the
frame exceeds a threshold. Additionally or alternatively, the
traction systems described above with respect to FIGS. 2-4 may
include hydraulics and/or other pressurized lines to move the
respective nozzles based on the curvature of the surface.
The example illustrated in FIGS. 3 and 4 is a top-down view where
the lever bracket extends horizontally (e.g., the lever bracket has
a longitudinal axis that is parallel to the rails when the lever
bracket is not moved by the truck frame). For example, FIG. 3
includes a Cartesian coordinate system, and the lever bracket has a
longitudinal axis parallel to the y-axis, as do the rails. The
truck frame has a longitudinal axis parallel to the x-axis.
However, in other examples, the lever bracket may extend
vertically, having a longitudinal axis that is perpendicular to the
rails. An example of this configuration is illustrated in FIGS.
5-6, which show side views 500 and 600, respectively, of the
journal bearing housings and lever brackets relative to a set of
rails 550. Herein, each respective lever bracket (506 and 507) is
configured to interact with the truck frame 510 at a top side and
be shifted laterally as the truck frame moves relative to the axle.
As shown, the lever brackets are coupled to the journal bearing
housings 502 and 503 via respective bellows 504 and 505.
FIG. 5 also includes a Cartesian coordinate system. As the views
500 and 600 are side views and not top-down views, the coordinate
system is shifted so that the rails remain parallel to the y-axis.
The lever brackets 506 and 507 have a longitudinal axis that is
parallel to the z-axis, and thus is orthogonal (e.g.,
perpendicular) to the longitudinal axis of the rails.
The nozzle (not shown in FIGS. 5-6) may be coupled to the bottom
end of the lever bracket and hence when the top end of the lever is
shifted to the left in FIG. 6 as the rail curves to the right, the
bottom end and hence the nozzle is shifted to the right.
Thus, a traction system configured to clean a surface such as a
rail may include a nozzle coupled to a pipe and positioned to
direct pressurized air onto a desired location of a surface (e.g.,
a rail), for example immediately ahead of a subsequent wheel/rail
contact point. The nozzle may be configured to track the position
of the rail so that the nozzle directs the air to the rail even as
the rail curves. In one example, the nozzle may include an
electromagnet that is energized responsive to an indication of
wheel slip, for example, and a flexible pipe that allows movement
of the nozzle as the rail curves. In another example, a mechanical
linkage between the truck frame and journal bearing housing may
shift the nozzle in a direction opposite the direction of the
lateral movement of the truck frame as the rail vehicle traverses a
curve, by an amount that depends on the lateral movement of the
truck frame relative to the axle. The mechanical linkage may
include a lever coupled to the journal bearing housing via a
bellows, where lateral motion of the truck frame moves a first end
of the lever and causes a second, opposite end of the lever to move
in the opposite direction, where the nozzle is coupled to the
second end of the lever. In some examples, both the electromagnet
and the mechanical linkage may be used together. For example, the
mechanical linkage may provide a more coarse adjustment to place
the nozzle in the vicinity of the track, while the electromagnet
may provide a more fine adjustment to position the nozzle at the
exact desired location relative to the track. Further, similar
rail-tracking mechanisms could be applied to other adhesion
generating systems, such as the sand blower described above.
The mechanical linkage alignment method for the nozzle described
above uses relative motion between the axle and the truck frame to
deflect the orientation of the nozzle so that it aims more towards
the direction of the curvature of the rail while in curves. This
alignment may be achieved in either the vertical or horizontal
plane, and each direction may have different sensitivity based on
the base angles between the rail and the nozzle. The alignment on a
tangent (e.g., straight) rail is not compromised, as oscillatory
motion of the wheel set predominately occurs at higher speeds where
the traction system is not activated nor is high tractive effort
utilized. The flexible pipe and/or bellows may be comprised of
rubber to accommodate motion to manage part fatigue.
By providing a traction system where the nozzle tracks the rail,
the nozzle may be aimed at the rail even when the entire traction
system itself is not directly over the rail. In doing so, tractive
effort that would normally be lost during curving on steep grades
may be maintained. Additionally, the tractive effort for a rail
vehicle starting up on flat curves or in locations where the nozzle
may be missing the rail may be increased. In this way, the
efficiency and adhesion performance of the rail vehicle may be
fulfilled throughout an entire trip and not just on straight track,
providing the customer with more advantages in defining train set
ups and maximizing gross train weight.
Turning now to FIG. 7, a method 700 for operating a traction system
is illustrated. Method 700 may be executed by a controller
according to non-transitory instructions stored in memory of the
controller, such as controller 214 of FIG. 2, in conjunction with a
traction system, such as the traction system 200 of FIG. 2 and/or
the tractions systems of FIGS. 3-4 and/or FIGS. 5-6. At 702, method
700 includes determining operating conditions. The determined
operating conditions may include vehicle operating conditions such
as engine speed, vehicle speed, engine load, wheel slip, tractive
effort, and/or other suitable conditions. The determined operating
conditions may further include travel surface conditions, such as
surface grade, surface curvature, and ambient conditions such as
ambient temperature. The determined operating conditions may be
determined based on output from on-board sensors (e.g., surface
curvature sensors, such as sensor 218 of FIG. 2) and/or from
information received from a remote system, such as a dispatch
center or GPS unit (e.g., ambient temperature, upcoming surface
conditions).
At 704, method 700 determines if application of an air stream from
the traction system is indicated. The application of the air stream
may include coupling the passage and associated nozzle of the
traction system to an air source in order to direct pressurized air
to the surface on which the vehicle is traveling. Accordingly, the
application of the air stream may be indicated when tractive effort
may be limited by surface conditions such as water, ice, or other
debris on the surface. In one example, the application of the air
stream may be indicated responsive to ambient temperature being
below a threshold temperature, responsive to moisture on the
surface being above a threshold level (e.g., when it is raining or
snowing), and/or responsive to the surface grade being greater than
a threshold grade. In another example, application of the air
stream may be indicated responsive to wheel slip greater than a
threshold slip. In a still further example, even when application
of the air stream is indicated based on surface conditions, the
application of the air stream may be delayed or ceased if certain
conditions are met. For example, the application of the air stream
may be ceased or delayed if the vehicle is in a certain location,
such as near people or while in a residential neighborhood, as the
air stream may produce undesirable noise, and/or the application of
the air stream may be ceased or delayed if the vehicle is at idle
or if the amount of air in the air source is below a threshold
level.
If application of the air stream is not indicated, for example if
desired tractive effort is being met, method 700 proceeds to 706 to
continue vehicle operation without the air stream supply. This may
include blocking a fluidic coupling between the nozzle/passage of
the traction system and the air source. Method 700 then
returns.
If application of the air stream is indicated, for example if
desired tractive effort is not being met due to lowered surface
friction, method 700 proceeds to 708 to supply the air stream to
the surface via the nozzle of the traction system. This may include
establishing a fluidic coupling between the nozzle/passage of the
traction system and the air source, such as by opening a valve
coupled between the air source and nozzle. Further, the air stream
may be applied while the nozzle of the traction system is at a
default position. At 710, method 700 optionally includes adjusting
one or more air stream parameters. For example, an amount and/or
velocity of the supplied air stream may be adjusted based on the
magnitude of the wheel slip or the operational mode of the vehicle,
such as if the vehicle is on a hill or if the vehicle is trying to
stop. For example, in response to a first, smaller amount of wheel
slip, the air stream may be supplied at a first, lower velocity,
while in response to a second, larger amount of wheel slip, the air
stream may be supplied at a second, higher velocity. In another
example, the air stream may be supplied at a higher velocity when
the vehicle is traveling up a hill relative to when the vehicle is
traveling on a level surface.
At 712, method 700 includes determining if surface curvature is
detected. The surface curvature may be detected according to output
from one or sensors (e.g., the sensor 218 of FIG. 2), the surface
curvature may be detected based on information received from a GPS
unit or other remote service, and/or the surface curvature may be
detected based on relative movement between the vehicle frame and
wheels of the vehicle. Further, the surface curvature may be
detected once the vehicle actually starts to traverse the curve, or
it may be detected in advance of the vehicle traversing the
curve.
If no surface curvature is detected, method 700 returns and
continues to supply the air stream if indicated, with the nozzle in
the default position. If surface curvature is indicated, method 700
proceeds to 714 to adjust the nozzle aiming direction. In one
example, as indicated at 716, adjusting the nozzle aiming direction
may include energizing an electromagnet of the nozzle. When the
vehicle is a rail vehicle such as locomotive, the surface that the
vehicle travels on may be made out of metal (e.g., a steel rail),
and hence energizing the electromagnet causes the nozzle to be
attracted to and follow the rail surface. Thus, when the rail
surface is curved, the nozzle will follow the curvature of the
rail, resulting in a change in the aiming direction of the
nozzle.
In another example, as indicated at 718, adjusting the nozzle
aiming direction may include actuating an actuator of the traction
system based on the detected curvature. For example, the nozzle
and/or passage coupled to the nozzle may be coupled to an actuator
such as a stepper motor, and the controller may send a signal to
the stepper motor to move the nozzle to an indicated aiming
direction that is a function of the surface curvature, as explained
above with respect to FIG. 2.
In a further example, as indicated at 720, adjusting the nozzle
aiming direction may include transferring relative motion between
the vehicle frame and wheel set to the nozzle, as explained above
with respect to FIGS. 3-6. For example, the flexible coupling of
the nozzle may be provided by a lever bracket mounted to a frame of
the vehicle and mounted to the passage (e.g., the pipe, tube, or
hose), and a resilient member may be coupled between the lever
bracket and a journal bearing housing or other structure of a lead
axle of the vehicle. The lever bracket transforms lateral movement
of the frame relative to the lead axle in a first direction to
lateral movement of the nozzle in a second, opposite direction, as
the curvature of the surface changes. Method 700 then returns.
FIG. 8 is a schematic diagram of a rail vehicle 1010, herein
depicted as a locomotive, configured to run on a rail 1012 via a
plurality of wheels 1014. As shown therein, the rail vehicle 1010
includes an engine 1016, such as an internal combustion engine. A
plurality of traction motors 1018 are mounted on a truck frame 20,
and are each connected to one or more of the plurality of wheels
1014 to provide tractive power to selectively propel and retard the
motion of the rail vehicle 1010.
As shown in FIG. 9, the rail vehicle 1010 may be a part of rail
vehicle consist 1022. The consist may include a lead locomotive
consist 1024, a remote or trail locomotive consist 1026, and plural
non-powered rail vehicles (e.g., freight cars) 1028 positioned
between the two consists 1024, 1026. The lead locomotive consist
1024 may include a lead locomotive, such as rail vehicle 1010, and
trail locomotive 1030. The remote locomotive consist 1026 also may
include a lead locomotive 1032 and a trail locomotive 1034. All of
the rail vehicles in the consist are sequentially mechanically
connected together for traveling along a rail track or other
guideway 1036.
As alluded to above, one or more of the locomotives 1010, 1020,
1032, 1034 in the consist 1022 may have an on-board compressed air
system for supplying one or more functional systems of the consist
1022 with compressed air. In an embodiment, each of the locomotives
in the consist may be outfitted with a compressed air system. In
other embodiments, fewer than all but at least one of the
locomotives in the consist may be outfitted with a compressed air
system. A flow diagram illustrating an exemplary compressed air
system 1040 is shown in FIG. 10. As shown therein, the compressed
air system 1040 includes an air compressor 42 driven by the engine
1016. As is known in the art, the air compressor 1042 intakes air,
compresses it and stores it in one or more main reservoirs 1044
on-board the locomotive. The compressed air from the main
reservoirs may then be utilized by various systems within the
consist, such as an air braking system, horn, sanding system, and
adhesion control/tractive effort system. As discussed below, the
main reservoir on-board each locomotive is fluidly coupled to the
main reservoir on-board the other locomotives in the consist
through a main reservoir equalizing (MRE) pneumatic trainline. As
used herein, "fluidly coupled" or "fluid communication" refers to
an arrangement of two or more features such that the features are
connected in such a way as to permit the flow of fluid between the
features and permits fluid transfer.
In an embodiment, the adhesion control/tractive effort system may
be any high velocity, high flow tractive effort control system
known in the art, such as those disclosed in PCT Application No.
PCT/US2011/042943, which is hereby incorporated by reference herein
in its entirety. For example, as shown in FIG. 11, a tractive
effort system 1046 includes a supply of pressurized air 1048. The
supply of pressurized air may be a main reservoir on board the
locomotive or the MRE pneumatic trainline (wherein the pressurized
air may be supplied by one or more air compressors within the
locomotive consist). The supply of pressurized air is fluidly
coupled, through a pressurized air control valve 1050, to a nozzle
1052 oriented to direct a high velocity, high flow of air jet to a
contact surface 1054 of the rail 1012. The tractive effort system
1046 may also include a reservoir 1056 for holding a supply of
tractive material 1058, such as sand, and a nozzle 1060 fluidly
coupled to the reservoir 1056 via a tractive material control valve
and oriented to direct a flow of tractive material 1058 to the
contract surface 1054 of the rail.
In an embodiment, the air nozzle 1052 is positioned to direct a
high flow, high velocity air jet to the rail in front of the lead
axle of a lead locomotive in a locomotive consist. In other
embodiments, both lead and trail locomotives may have tractive
effort systems 1046. In addition, tractive material nozzle 1060 is
positioned to direct a flow of tractive material to the rail in
front of and behind both the lead and trail axles of a
locomotive.
FIG. 12 shows two locomotives 1010, 1030 coupled together in a
consist. Each locomotive has a tractive effort system 1046 thereon.
As shown therein, an air compressor 1042 on board each locomotive
is configured to supply compressed air to a main reservoir 1044.
The main reservoirs 1044 of each locomotive are fluidly coupled to
one another via the MRE pneumatic trainline 1062. In this manner,
each locomotive with an air compressor 1042 and main reservoir 1044
feeds the MRE trainline 1062 through a restrictive path. This
restriction may be a specific orifice or the restriction associated
with an air dryer. The main reservoirs 1044 of each locomotive are
also fluidly coupled to the air nozzle 1052 of the tractive effort
system 1046 for supplying the nozzles with pressurized air.
Moreover, as shown therein, each tractive effort system 1046 is
electrically coupled to a control unit 1064 on board the
locomotives for controlling the tractive effort systems in
accordance with embodiments of the present invention, as discussed
below.
While FIG. 12 illustrates a two locomotive consist with tractive
effort systems 1046 on each locomotive, there may be any
combination of both tractive effort quipped and non tractive effort
equipped locomotives in a conventional or distributed power
consist. Moreover, the locomotives in the consist may include
locomotive to locomotive communication in the form of a standard
wired trainline, a high bandwidth communications link such as
trainline modem or Ethernet trainline, or distributed power (remote
or radio controlled). In some embodiments, there may be no
communication between locomotives.
In an embodiment, a system and method for tractive effort consist
optimization is provided. As will be readily appreciated, for any
locomotive consist, such as that shown in FIG. 12, there will
typically be at least one air compressor available to contribute to
the total compressed air need of the consist. In an embodiment, a
method for tractive effort consist optimization includes maximizing
the air to the lead-most tractive effort system position. If
locomotive to locomotive communication is present, then the
detailed configuration of the tractive effort system configuration
within the consist may be easily determined/sensed using known
methods and shared among the locomotives.
More typically, however, each locomotive may only know the
lead/trail status of itself, the air flow to the brake pipe if the
locomotive is a lead locomotive, and the direction of the
locomotive (short hood/long hood). In this situation, at least one
of the locomotives within the consist must be able to determine if
there is a tractive effort system in the consist. In connection
with this, FIG. 13 is a flow diagram illustrating a method to
estimate the air flow delivered to the MRE pneumatic trainline
1062. As shown therein, in an embodiment, a control unit on-board
one of the locomotives may utilize integrated control information
regarding air compressor speed and load state, reservoir air
pressure derivatives and the states of other pneumatic actuators or
loads within the vehicle to develop an approximate value of air
flow to the MRE pipe 1062. From this value, the control unit is
able to determine whether or not a particular locomotive is
configured with a tractive effort system.
In an embodiment, for a lead locomotive having a tractive effort
system without variable flow, determining tractive effort system
configuration is not needed. In this situation, the tractive effort
system 1046 of the lead locomotive is enabled by the control unit
1064, e.g., by actuating the air control valve 1050, until the
pressure in the main reservoir 1044 is less than approximately less
than 110 psi (758 kPa). For a lead locomotive having a tractive
effort system with variable flow, however, the control unit 1064 is
configured to automatically adjust the flow through the air control
valve 1050 to the maximum level that maintains a pressure in the
main reservoir 1044 above approximately 110 psi. In both of these
instances, the air compressor 1042 is controlled by the control
unit 1064 to maximum flow if the main reservoir pressure is less
than approximately 135 psi (930 kPa) and is shut off at
approximately 145 psi (1000 kPa).
In an embodiment, for a lead locomotive without a tractive effort
system and having a communication link to a trail locomotive, the
configuration of the tractive effort system(s) within the consist
is first determined via the communication link. As discussed above,
if there is no communication link to a trail locomotive, a tractive
effort system elsewhere in the consist may be determined by
estimating the air flow delivered to the MRE pipe 1062. In both of
these situations, if a trail locomotive has a tractive effort
system, the air compressor is loaded to maximum flow if the main
reservoir pressure is less than approximately 135 psi and is shut
off at approximately 145 psi.
In another embodiment, for a trail locomotive having an on-board
tractive effort system and having a communication link to a lead
locomotive, the configuration of the tractive effort system(s)
within the consist is first determined via the communication link.
If a more leading locomotive has a tractive effort system, the
tractive effort system of the trail locomotive is enabled so long
as the pressure within the main reservoir 1044 of the trail
locomotive is above approximately 141 psi. As will be readily
appreciated, this maximizes the air to the more leading locomotive.
As used herein, "more leading" refers to a position of a locomotive
within a consist physically ahead of another locomotive within the
same consist. If there is not a more leading locomotive having a
tractive effort system within the consist, the tractive effort
system of the trail locomotive is enabled as long as the pressure
within the main reservoir 1044 is above approximately 110 psi. If
it determined that the trail locomotive is a final trail locomotive
within the consist, and in a long hood direction, the tractive
effort system 1046 is disabled by the control unit 1064. In any of
these situations, the air compressor is loaded to maximum flow if
the main reservoir pressure is less than approximately 138 psi and
is shut off at approximately 145 psi.
For a tail locomotive having a tractive effort system wherein there
is no communication to a lead locomotive in the consist, the
configuration of tractive effort systems in the consist may again
be determined by estimating the air flow delivered to the MRE pipe
1062. If another tractive effort system is detected/determined
within the consist, the tractive effort system of the trail
locomotive is enabled so long as the pressure within the main
reservoir 1044 of the trail locomotive is above approximately 141
psi. In this situation, the air compressor is loaded to maximum
flow if the main reservoir pressure is less than approximately 138
psi and is shut off at approximately 145 psi.
Lastly, for a trail locomotive without a tractive effort system,
the configuration of tractive effort systems elsewhere in the
consist is determined through the communications link to the lead
locomotive, if present, or by estimating the MRE pipe air flow, as
discussed above. If it is determined that another locomotive has a
tractive effort system, then the air compressor is loaded to
maximum air flow if the main reservoir pressure is less than
approximately 135 psi and is shut off at approximately 145 psi.
As discussed above, a tractive effort system provides an increase
in tractive effort by applying a high velocity, high flow air jet
to the contact surface of a rail. As also disclosed above, various
control logic is utilized to optimize the use of the tractive
effort systems within a consist in dependence upon the position of
the tractive effort systems within the consist, the capability of
the air compressors within the consist and the compressed air
demands of other systems in the consist. In order to sustain the
high flow level required for the tractive effort systems to provide
peak tractive effort performance improvements, flow to or through
the tractive effort systems must be maximized while maintaining
main reservoir pressure above a certain lower threshold.
Accordingly, an embodiment of the present invention is directed to
a system and method for optimizing the flow of compressed air to a
tractive effort system and, more particularly, to a system and
method for varying the flow to a tractive effort system (or to the
air nozzle 1052 thereof) in order to maintain a required lower
threshold pressure within the main reservoir 1044.
With reference to FIG. 14, a variable flow system 1100 in
accordance with an embodiment of the present invention is shown. As
shown therein, an air compressor 1102 compresses air, which is
stored in a main reservoir 1104 on board a rail vehicle or
locomotive. The main reservoir 1104 is fluid communication with a
tractive effort system 1106, such as that described above, through
a first pathway 108 having a large orifice 1110 therein and a
second pathway 1112 having a small orifice 1114 therein. A first
valve, such as solenoid valve 1116 selectively controls the flow of
compressed air through the first pathway 1108 and the large orifice
1110 to the tractive effort system 1106 and a second valve, such as
second solenoid valve 1118, selectively controls the flow of
compressed air through the second pathway 1110 and the small
orifice 1114 to the tractive effort system 1108. A control unit is
electrically coupled to the first and second valves 1116, 1118 and
is configured to selectively control the first and second valves
1116, 1118 between a first state, in which compressed air flows
through the valves 1116, 1118, through the orifices 1110, 1114 and
to the tractive effort system 1106, and a second state in which
compressed air is prevented from flowing through the valves 1116,
1118.
In operation, the control unit detects the pressure within the main
reservoir 1104 and controls the flow of compressed air from the
main reservoir through either or both of the large orifice 1110 and
small orifice 1114 in dependence upon the detected pressure.
Generally, if tractive effort is needed and the pressure within the
main reservoir is close to a predetermined lower threshold
pressure, the control unit 1120 may control the second solenoid
valve 1118 to its second state and the first solenoid valve 1116 to
its first state such that a flow of compressed air through the
small orifice 1114 only is permitted. As will be readily
appreciated, a lower pressure in the main reservoir 1104 may be a
result of other systems utilizing the available supply of
compressed air, air compressors operating at less than maximum
capacity, etc. If however, the pressure within the main reservoir
1104 is sufficiently high, the control unit 1120 may control both
the first and second valves 1116, 1118 to their respective first
states such that compressed air is permitted to flow through both
the large and small orifices 1110, 1114. As will be readily
appreciated, by controlling both valves to their respective first
positions, maximum flow to the tractive effort system, and thus
maximum tractive effort improvement, is achieved.
In an embodiment, with both the first and second valves 1116, 1118
in their respective first (enabled) states, thus enabling flow
through both the large orifice 1110 and small orifice 1114, a flow
of approximately 300 cubic feet per minute (cfm) to the nozzle(s)
of the tractive effort system 1106 may be realized. In an
embodiment, with only the first valve 1116 in its first (enabled)
state, and thus flow through the large orifice 1110 only, a flow of
approximately 225 cfm may be realized. Similarly, with only the
second valve 1118 in its first (enabled) state, and thus flow
through the small orifice 1114 only, a flow of approximately 150
cfm may be realized. Given these expected flow rates when flow is
enabled through either the large, small or both orifices 1110,
1114, a control strategy that maximizes the flow to the tractive
effort system in dependence upon the available pressure within the
main reservoir may be generated. As will be readily appreciated,
the flow to a tractive effort system may be maximized by cycling
between the options described above (e.g., first valve enabled,
second valve disabled; second valve enabled, first valve disabled;
both valves enabled; both valves disabled), in dependence upon the
pressured detected within the main reservoir at any given time.
With reference to FIG. 15, a variable flow system 1150 in
accordance with another embodiment of the present invention is
shown. As shown therein, an air compressor 1152 compresses air,
which is stored in a main reservoir 1154 on board a rail vehicle or
locomotive. The main reservoir 1154 is fluid communication with a
tractive effort system 1156, such as that described above, through
a pathway 1158 having a continuously variable orifice 1160 therein.
The size of the continuously variable orifice 1160 is controllable
by a control unit 1162. In operation, when use of the tractive
effort system 1106 is necessary to increase tractive effort, the
pressure within the main reservoir 1154 is continuously monitored
and the size of the variable orifice 1160 is varied in order to
maintain the pressure in the main reservoir 1154 above a
predetermined lower threshold pressure. In an embodiment, the lower
threshold pressure is approximately 110 psi. In particular, the
size of the orifice is adjusted based on the available main
reservoir pressure. As discussed above, maintaining the pressure
within the main reservoir 1154 above a lower threshold, namely 110
psi, is necessary to ensure that there is sufficient pressure to be
utilized by other functional systems within the consist. In an
embodiment, the size of the orifice is controlled by a continuously
variable orifice valve.
In other embodiments, other flow control devices may be utilized to
control the flow of air from the main reservoir to a tractive
effort system in order to maintain a predetermined lower threshold
pressure in the main reservoir. For example, the present invention
contemplates the use of position displacement and/or vein valve
devices to allow variable flow that enables the system to maximize
air flow at any given time. In yet another embodiment, a secondary
compressor may be utilized to either solely supply air to the
tractive effort system, to supplement the compressed air supplied
by the main reservoir, or to supply air to the main reservoir to
maintain the pressure therein above the predetermined lower
threshold.
Adhesion control systems and methods according to the present
invention also provide the ability to disable a tractive effort
system(s) within a consist in cases where enablement of the
tractive effort system may be undesirable. For example, it may be
desirable to disable the tractive effort system(s) in situations
where operation of the system(s) may have a negative impact on
locomotive performance. In an embodiment, the control unit may be
configured to disable the tractive effort enhancement system(s)
when one or more adverse conditions are present. In particular, the
control unit on a locomotive, such as a lead locomotive, may
automatically disable the tractive effort system on-board the
locomotive in an area where the audible noise generated during use
of the tractive effort system is objectionable. For example,
information regarding residential or noise-sensitive areas may be
stored in memory of a control unit and GPS may be utilized to
monitor the geographical position of a consist. When the consist
approaches an area stored in memory as being a noise-sensitive
area, the control unit may automatically suspend use or disable the
tractive effort system. FIG. 16 is a block diagram illustrating the
implementation of a smart-disable control strategy wherein the
adverse condition is a noise-sensitive area. (Generally, "adverse"
condition refers to a condition which is designated as a basis for
control of the tractive effort system, which may include turning
off or disabling the tractive effort system.)
In another embodiment, the control unit may disable the tractive
effort system in a consist position where an active tractive effort
system may have minimal positive or even negative impact on overall
consist tractive effort (e.g., due to the location of a consist on
grade and the position of the tractive effort system within the
consist). FIG. 17 is a block diagram illustrating the
implementation of a smart-disable control strategy wherein the
adverse condition is for consist characteristics that translate to
the tractive effort system having a minimal positive impact.
In other embodiments, the control unit may be configured to disable
the tractive effort system when the locomotive on which the
tractive effort system is configured is traversing a curve of a
sufficiently small radius to cause reduced performance. As will be
readily appreciated, reduced performance may be due to, for
example, the misalignment of the nozzle of the tractive effort
system relative to the contact surface of the rail, among other
factors. In connection with this embodiment, the radius of a curve
may be sensed or calculated and/or various sensors may sense the
position of the nozzle of the tractive effort system relative to
the rail. These sensors may transmit data to the control unit and
the control unit may disable the tractive effort system when
misalignment of the nozzle with the contact surface of the rail is
sensed. In addition, track data representing a curvature of the
track at various locations may be stored in memory, and the control
unit may be configured to disable the tractive effort system when
the consist travels through these stored locations, as determined
by GPS. FIG. 18 is a block diagram illustrating the implementation
of a smart-disable control strategy based on GPS heading
information. As shown therein, in an embodiment, locomotive speed
and heading velocity is input into the control system. A curve
calculation is carried out to determine the amount of curve in the
track. If the curve is greater than approximately 4 degrees, the
tractive effort system is disable. If the curve is less than
approximately 4 degrees, the tractive effort system is enabled.
Similarly, FIG. 19 is a block diagram illustrating the
implementation of a smart-disable strategy based on GPS location
information and a track database. As shown therein, under this
method, information regarding the curvature of a track at various
locations along a route of travel is stored in memory. GPS is
utilized to sense a location of the consist such that when the
consist is in a location where a "severe" curve is known to exist,
the tractive effort system will be disable by the control unit. As
used herein, "severe curve" means a curve greater than
approximately 4 degrees.
In yet other embodiments, the control unit may be configured with
an adaptive control strategy capable of "learning" of a negative
impact that enablement of a tractive effort system may have. Causes
of negative impact include adverse weather conditions that are
found to disturb the normally positive impact of a tractive effort
system such as snow on the roadbed (which could blow up on the rail
if the system were enabled) or cold temperatures (which may
interact with the air blast from the nozzle) to cause a freezing of
moisture on the rail). Other adverse conditions may include unusual
dust or debris on the roadbed which may be blown onto the track by
the system to reduce adhesion. FIG. 20 is a block diagram
illustrating the implementation of a smart-disable strategy wherein
the control unit disables the tractive effort system if a negative
impact of the tractive effort system is detected or measured. In
particular, as shown in FIG. 20, the control unit may be configured
to disable the tractive effort system if effectiveness of the
system does not reach a predetermined threshold. Systems and
methods for determining effectiveness of a tractive effort system
are discussed hereinafter.
In connection with the adhesion control systems and methods
described above, the tractive effort enhancement systems are
configured to automatically enable or disable when needed to
produce an increase in tractive effort in dependence upon tractive
effort position within a consist, sensed track conditions, sensed
position of the consist, etc. In certain situations, however, it is
also desirable to provide a means for an operator to manually
enable one or more tractive effort systems on the consist prior to
the control unit automatically enabling such systems. That is, it
is sometimes desirable to manually enable a tractive effort system
regardless of any automatic control functionality, such as that
disclosed hereinbefore. As will be readily appreciated, this may be
advantageous where an operator recognizes a rail condition
visually, based on past experiences or other reasoning. Moreover,
an operator may need to quickly and/or momentarily disable the
tractive effort system(s) due to special circumstances such as to
avoid debris or to avoid kicking up loose particles or debris on
the road bed that could damage the locomotives or other nearby
equipment.
In an embodiment, a tractive effort system 1200 having an operator
interface is provided. As shown in FIG. 21, the tractive effort
system 1200 may be substantially similar to the tractive effort
systems disclosed above and includes a supply of compressed air,
such as a main reservoir 1202 on-board a locomotive or a MRE
pneumatic trainline, a nozzle 1204 fluidly coupled to the main
reservoir 1202 for directing a high flow of air to a contact
surface of the rail, a control valve 1206 for selectively enabling
or disabling the flow of compressed air from the main reservoir
1202 to the nozzle, and a control unit 1208 electrically coupled to
the control valve 1206 for controlling the valve 1206, and thus the
tractive effort system, between its enabled state and disabled
state. As shown in FIG. 21, an operator interface 1210 is
electrically coupled to the control unit 1208.
The operator interface 1210 includes a momentary disable switch
1212 and a monostable button 1214. In an embodiment, the momentary
disable switch 1212 may be a hardware spring return mono-switch
which is biased to an "enable" position in which tractive effort
system 1200 is controlled automatically in accordance with the
control logic and methods disclosed above. The momentary disable
switch 1212 is movable against the bias by an operator to a
"disable" position in which a signal is sent to the control unit
1208, and thus to the valve 1206 of the tractive effort system
1200, to disable the tractive effort system. In an embodiment, an
operator must hold the switch 1212 in the "disable" position
continuously to maintain the tractive effort system in the manually
disabled state. If the operator releases the momentary disable
switch 1212, the switch springs back to the "enable" position
wherein automatic control of the tractive effort system 1200 by the
control unit 1208 is resumed. As will be readily appreciated, the
momentary disable switch 1212 may be useful in situations where an
operator wishes to disable the air blast to the rail for a short
period of time, such as when crossing a public roadway or the
like.
The monostable button 1214 is configured to toggle the state of the
tractive effort system 1200 between "enabled" and "disabled" when
pressed by an operator. The state, whether enabled or disabled, may
be displayed to the operator on a display 1216. The indication to
the operator of the disabled or enabled state of the tractive
effort system 1200 may be in the form of a light or screen icon on
the display 1216. In an embodiment, the indication may be a dial
indicator or audio indicator, such as an audible tone. In an
embodiment, the control unit 1208 is configured to control the
tractive effort system 1200 back to its enabled state after at
least one of a designated time has elapsed, a designated distance
has been traversed, a designated throttle transition has occurred,
the direction hand has been centered, a manual sand switch has been
pressed or changed state, a certain vehicle speed change or level
has occurred, the locomotive is within a certain geographical
region, certain predetermined locomotive power or tractive effort
levels have been attained, and/or certain other operator actions
have been detected or sensed. FIG. 22 is a state machine diagram
illustrating how the control unit 1208 responds to direct operator
inputs (i.e., the momentary disable switch 1212 and monostable
button 1214) to control operation of the tractive effort system
1200. In this implementation, a timer or a control system power-up
is used to resent the tractive effort system 1200 to an enabled
state.
As discussed above, tractive effort systems in accordance with the
present invention may, in addition to having a high-flow rate
compressed air nozzle, may include a sanding nozzle for
distributing sand or tractive material to the contact surface of
the rail. Such a system was described above with reference to FIG.
11. As will be readily appreciated, the tractive material/sand may
be mixed with a flow of pressurized air and driven at high velocity
onto the rail to increase tractive effort, or may be simply
deposited onto the contact surface of the rail without being
entrained in a flow of pressurized air. Indeed, sanding has been
commonly used in the rail industry to enhance the friction between
the wheel/rail interface through sanding at the contact surface of
the rail. Customarily, sand or other tractive material is applied
in front of an axle in wet rail conditions or in other conditions
where slippage may occur. Known sanding strategies include
"automatic sand," wherein sand is automatically applied in front of
both trucks of a locomotive, "manual lead," wherein sand is applied
in front of the leading locomotive axle only and is manually
enabled by an operator, and "manual trainline," wherein sand is
applied in front of both trucks of all locomotives within the
consist and is manually enabled by an operator.
With improvements in tractive effort systems, such as the
improvements contemplated by the adhesion control systems and
methods of the present invention, higher tractive effort may be
attained than was previously possible. These improvements in
tractive effort may be leveraged to reduce the amount of sand used.
As will be readily appreciated, reducing the amount of sand used is
desirable, as it reduces railroad capital expense. Accordingly, the
present invention also provides a control system and method that
reduces the amount of sand or tractive material utilized.
In an embodiment, a system for controlling a consist of rail
vehicles includes a tractive effort system on-board a rail vehicle.
The tractive effort system may be of the type disclosed above in
connection with FIG. 11 having both air blast and sand dispensing
capabilities. In other embodiments, the sand dispensing may be
separate from the compressed air pathway, as discussed above. A
control unit, such as that disclosed above, is electrically coupled
to the rail vehicle and is configured to control the tractive
effort system to dispense both tractive material/sand, sand only or
air only. In an embodiment, the control unit may include a
processor having a control strategy stored in memory that is
executable to provide a high-flow jet of compressed air as a
preference before applying sand to the rail.
According to an embodiment of the present invention, for a consist
utilizing an "automatic sand" strategy, the control unit may
configured to monitor slip, individual axle tractive effort and
overall locomotive tractive effort and horsepower, as hereinafter
discussed. The control unit may include a control strategy wherein
sand is enabled as a backup to compressed air only as a function of
at least one of locomotive speed, locomotive tractive effort, time
since the air only mode was activated, distance traversed since the
tractive effort system was activated, geographical location,
operator input and measured or inferred tractive effort reservoir
levels. In an embodiment, the control system may be configurable to
realize more sand savings as opposed to high tractive effort, and
vise-versa.
In yet another embodiment of a system for reducing the amount of
sand/tractive material utilized, the control system may be
configured to delay automatic sanding after the air only blast as
long as a certain level of tractive effort is attained. This
tractive effort threshold may be a function of a speed such that as
the consist slows toward a stall or is slipping, a more aggressive
sand application is initiated by the control unit/control system.
In an embodiment, a tractive effort threshold is input into the
control unit or stored in memory. Above this tractive effort
threshold, auto-sanding is not initiated. This threshold may be
automatically increased as speed is reduced so that at some lower
speed, sand is always applied if there are any axels on the
locomotive which are limited in tractive effort due to wheel slip.
FIG. 23 illustrates an exemplary tractive effort threshold as a
function of locomotive speed. FIG. 24 is a state machine diagram
illustrating how the tractive effort threshold may be utilized by
the control unit to control operation of the tractive effort system
(i.e., sand only, air only or sand and air) in order to reduce the
amount of sand or tractive material used.
According to another embodiment of the present invention, a control
system and method for reducing the amount of sand utilized under a
"manual lead" sand strategy is provided. As discussed above, the
manual lead axle sand command is typically issued when an operator
wants to sand the lead axle independent of the automatic sand
state. FIG. 25 is a state machine diagram illustrating an exemplary
sand reduction control strategy for manual lead axle sanding. As
shown therein, upon initiation of "manual lead" sanding, the air
blast mode of the tractive effort system is automatically initiated
as well. Once the air blast mode of the tractive effort system is
enabled, it is maintained in the enabled state even if the operator
input to the enable "manual lead" sand is removed. In this
embodiment, the control unit is configured to deactivate or disable
the tractive effort system (i.e., cease air blast) after some time
or some distance. In another embodiment, the control unit is
configured to deactivate or disable the tractive effort system
(i.e., cease air blast) if the consist is past the apparent grade
or slippage challenge as indicated by realized high train speeds or
a throttle reduction. The embodiments of the present invention
relating to sand reduction systems and methods disclosed herein are
particularly applicable to situations where the throttle is in the
"motoring position." It is contemplated, however, that similar
control strategies for sand reduction are applicable in "dynamic
braking modes" as well.
According to another embodiment of the present invention, a control
system and method for reducing the amount of sand utilized under a
"manual trainline" sand strategy is provided. As discussed above,
the manual trainline sand command is typically issued when an
operator desires to sand the lead axle on each truck of the
trainline in addition to or independent of automatic sand. FIG. 26
is a state machine diagram illustrating an exemplary sand reduction
control strategy for manual trainline sanding. As shown therein,
upon initiation of "manual trainline" sanding, the air blast mode
of the tractive effort system is automatically initiated as well.
Once the air blast mode of the tractive effort system is enabled,
it is maintained in the enabled state even if the operator input to
the enable "manual trainline" is removed. In this embodiment, as
with the sand saving method under "manual lead" sanding disclosed
above, the control unit is configured to deactivate or disable the
tractive effort system (i.e., cease air blast) after some time or
some distance, or if the consist is past the apparent grade or
slippage challenge as indicated by realized high train speeds or a
throttle reduction.
In connection with the control systems and methods for high flow
rate tractive effort systems disclosed above, the present invention
also relates tractive effort diagnostic systems and methods. In
particular, the present invention is also directed to systems and
methods for detecting clogs in a tractive effort system, detecting
leaks in a tractive effort system and for measuring or detecting
the effectiveness of a tractive effort system. As will be readily
appreciated, diagnosing the "health" of a tractive effort system or
systems on board a rail vehicle consist is important to achieving
and maintaining optimum tractive effort during travel. As will be
readily appreciated, if a tractive effort system is clogged or has
a leak, it may function less than optimally and provide less than
optimal results. Moreover, tractive effort control systems may
utilize information regarding the "health" of the tractive effort
systems to generate and execute a more tailored control strategy
therefor.
In one embodiment, a system and method for detecting clogs in a
tractive effort system on-board a rail vehicle is provided. As
discussed above, the tractive effort systems contemplated by the
present invention utilize substantially high flow rates to clear
debris from the rail of a track to increase tractive effort. These
high flow rates used allow significant reductions in flow to be
detected. In particular, the impact of air usage from enablement of
a tractive effort system and the load on the air compressor to
replace the compressed air in the main reservoir of a given rail
vehicle or locomotive may be monitored.
As will be readily appreciated, any system that utilizes air from
the main reservoir on-board a locomotive causes the pressure within
the main reservoir to suddenly drop when the system is enabled.
This is a direct result of compressed air being drawn from the
reservoir faster than the air compressor can replace it. As the
tractive effort systems having high flow air jets contemplated by
the present invention are large consumers of compressed air,
enablement of the system immediately results in a large, sudden and
detectable drop in the pressure in the main reservoir. As the
pressure in the main reservoir drops, the air compressor is
activated to replace the compressed air within the main
reservoir.
In an embodiment, as illustrated in FIG. 27, a method for detecting
clogs in a tractive effort system on-board a rail vehicle includes
comparing compressor air flow before ("baseline") and after
("secondary") the activation of the tractive effort system.
Importantly, however, because there are other systems on board the
consist that utilize compressed air, such as air brakes, sander
control valves, horns, and other actuators, this flow comparison is
best made when the state of these other devices is constant (and
thus the air compressor load state is constant). In an embodiment,
the compressor flow may be estimated in normalized volume rates. In
another embodiment, the compressor flow may be estimated in mass
flow based on compressor displacement and speed. FIG. 28 is a state
machine diagram illustrating a method for detecting the change in
non-tractive effort system air flow, i.e., for determining when the
state of all air-consuming devices is constant and thus the air
compressor load state is steady. FIG. 29 is a flow diagram
illustrating a method for estimating air compressor and tractive
effort system flow, as described above. FIG. 30 is a state machine
diagram illustrating a method for detecting clogs in a tractive
effort system.
As best shown in FIG. 30, a method for detecting clogs first
includes the step of determining an air flow rate from the
compressor to the main reservoir and a corresponding compressor
load value under steady conditions. As used herein, steady
conditions is intended to mean when the state of other air
consuming devices is generally constant. This initial air flow rate
and compressor load value/air load state may be referred to as a
"baseline" air flow rate and baseline compressor load value/air
load state. Once the air load state is steady, the tractive effort
system is enabled by the control system for a predetermined period
of time. At the expiration of this period, a secondary air flow
rate and/or compressor load value is then assessed and compared to
the baseline air flow rate and/or compressor load value. If the
secondary air flow rate is greater than the baseline air flow rate
plus a predetermined "buffer" (generally representing tractive
effort system expected air flow), then the tractive effort system
is diagnosed as "healthy" with respect to any clogs. If, however,
the secondary air flow rate is less than the baseline air flow rate
plus the "buffer," then the tractive effort system is diagnosed as
"clogged." Based on this diagnosis, the control system may be
configured to automatically disable the clogged tractive effort
system and instead utilize another tractive effort system on-board
another rail vehicle in its place.
In addition to detecting clogs within a tractive effort system by
comparing compressor air flow before and after activation of the
tractive effort system, system leaks may be diagnosed by detecting
larger than expected compressor air flows when the system is
activated as compared to when it is disabled. In an embodiment, the
region where leaks can be detected is on the load side of the
solenoid valve 50 as shown in FIG. 11. As will be readily
appreciated, the detection of leaks within the system is important,
as large leaks can tax the compressor to the point it cannot
maintain system pressure above required levels.
As illustrated by the state machine diagram of FIG. 31, a method
for detecting leaks in a tractive effort system includes first
ensuring that the air load state is "steady," as discussed above.
Once the air load state is steady, the tractive effort system is
enabled by the control system for a predetermined period of time.
At the expiration of this period, a secondary air flow rate is
measured. If the secondary air flow rate is greater than a
predetermined threshold flow rate value based on the expected flow
rate of the tractive effort system, a leak is diagnosed. If the
secondary air flow rate is less than the predetermined threshold
flow rate value, then the tractive effort system is diagnosed as
"healthy" with respect to any leaks. If a leak is detected, the
tractive effort system may be disabled or restricted in its use by
the control system. In addition, based on this diagnosis, the
control system may elect to utilize another tractive effort system
within the consist in its place in accordance with the control
logic described above.
In addition to the above, the present invention also provides a
method for determining the effectiveness of a tractive effort
system. In particular, the control system of the present invention
is configured to automatically determine the impact of the tractive
effort system on tractive effort and to take appropriate control
action to accommodate the performance. As illustrated by the state
machine diagram of FIG. 32, a method for determining the
effectiveness of a tractive effort system includes enabling a
tractive effort system for a predetermined travel distance. In an
embodiment, the predetermined travel distance is at least 1
locomotive length. In an embodiment, the predetermined travel
distance is more than 2 locomotive lengths. After the tractive
effort system has been enabled for a predetermined travel distance,
a first tractive effort is sampled, along with sand states, speed,
notch, heading and curve measure. The tractive effort system is
then disabled by the control system and a delay of approximately 2
locomotive lengths is initiated to allow for the impact of the
tractive effort system to take effect. If speed has changed by more
than approximately 2 miles per hour, notch has changed, or
curvature has changed by more than approximately 3 degrees, then
use of the tractive effort system is aborted. If not, a second
tractive effort is sampled. The tractive effort of the system is
then determined by subtracting the second tractive effort sampled
value from the first tractive effort sample value. Depending on the
outcome of this comparison, tractive effort system may be enabled
once again to increase tractive effort.
In an embodiment, the state machine for effectiveness detection
illustrated in FIG. 32 may interact with a tractive effort system
state machine, as shown in FIG. 33. In particular, this method for
determining tractive effort system effectiveness may be utilized in
connection with the smart-disable control strategy as shown in FIG.
20 and as discussed above. In this embodiment, if certain tractive
effort system permissive conditions are met, such as speed is
greater than approximately than 12 mph, throttle is approximately
notch 7 or more, main reservoir pressure is greater than
approximately 110 psi and either automatic or manual sand is
enabled, then the tractive effort system is enabled after a
predetermined delay. In an embodiment, the delay may be
approximately 5 seconds. As shown therein, the tractive effort
system may be maintained in its enabled state until the pressure in
the main reservoir drops below approximately 110 psi. In an
embodiment, the tractive effort system may be maintain in its
enabled state until speed is greater than approximately 15 mph or
throttle is approximately less than notch 6. Moreover, in an
embodiment tractive effort system effectiveness may also be
assessed and the system either disabled or maintained in an enabled
state in dependence upon the determined effectiveness, as discussed
above.
As will be readily appreciated, the ability to assess the
effectiveness of a tractive effort system provides a number of
advantages. In particular, assessment of the effectiveness provides
performance information that can be used to aid in design
improvements. In addition, defects or shortcomings in system
effectiveness can be utilized to drive repair. Moreover,
determining effectiveness of a tractive effort system allows a
negative impact on tractive effort to be detected, such that a
control action may be undertaken to disable the system until a
period of time has elapsed or a change in location or rail
condition has occurred, as hereinbefore discussed.
An embodiment of the present invention relates to a system for
controlling a consist of rail vehicles or other vehicles. The
system includes a control unit electrically coupled to a first rail
vehicle in the consist, the control unit having a processor and
being configured to receive signals representing a presence and
position of one or more tractive effort systems on-board the first
vehicle and other rail vehicles in the consist, and a set of
instructions stored in a non-transient medium accessible by the
processor, the instructions configured to control the processor to
create a optimization schedule that manages the use of the one or
more tractive effort systems based on the presence and position of
the tractive effort systems within the consist. The control unit
may be configured to maximize a supply of air to a lead-most
tractive effort system. The control unit may configured to
determine the presence of the one or more tractive effort systems
on-board the rail vehicles in dependence upon at least one of air
compressor speed and load state, reservoir pressure derivatives and
a status of other loads within the rail vehicles. The control unit
may be configured to detect the presence of a tractive effort
system within the consist by estimating an air flow within a MRE
pneumatic line. Moreover, the control unit may be configured to
receive the signals representing the presence and position of one
or more tractive effort systems on-board the rail vehicles via a
communication link between the first rail vehicle and the other
rail vehicles. The communication link may be a high-bandwidth
communications link. The system may also include a compressed air
reservoir fluidly coupled to one of the tractive effort systems for
supplying compressed air, and the control unit may be configured to
adjust the flow of compressed air from the reservoir to the
tractive effort system to maintain a pressure within the reservoir
above a lower threshold. The lower threshold may be approximately
110 psi. Alternatively, the control unit may be configured to
enable one or more of the tractive effort systems until a pressure
within the reservoir reaches a lower threshold pressure.
Another embodiment of the present invention relates to a method for
optimizing a consist of at least first and second rail vehicles or
other vehicles. The method includes the steps of determining a
configuration of tractive effort systems within the consist and
enabling the tractive effort systems in dependence upon the
determined configuration to increase tractive effort. The method
may also include the step of maximizing a flow of air to a
lead-most tractive effort system. The step of determining the
configuration of tractive effort systems within the consist may
include estimating the flow of air through a MRE pneumatic line.
Moreover, the method may include the step of adjusting a flow of
air to one of the tractive effort systems to maintain a pressure
within a compressed air reservoir above a lower threshold. The
method may further include the step of, wherein the first and
second rail vehicles each have a tractive effort system thereon,
regulating the pressure in a compressed air reservoir of the second
rail vehicle above approximately 140 psi (965 kPa) and regulating
the pressure in a compressed air reservoir of the first rail
vehicle above approximately 110 psi. The method may also include
loading an air compressor to maximum flow.
Another embodiment of the present invention relates to a method of
optimizing a flow of air to a tractive effort system of a rail
vehicle or other vehicle. The method includes the steps of
providing a supply of pressurized air from a reservoir to the
tractive effort system, and varying the flow of air to the tractive
effort system to maintain a pressure in the reservoir above a
predetermined lower threshold. Varying the flow of air may include
selectively directing the flow of air from the main reservoir
through one of a first orifice and a second orifice in dependence
on a detected air pressure in the reservoir, wherein the first
orifice having a larger outlet area than the second orifice.
Varying the flow of air may include selectively controlling a size
of an orifice in an air flow path between the reservoir and a
nozzle of the tractive effort system in dependence upon an
available air pressure in the reservoir. The size of the orifice
may be controlled by a continuously variable orifice valve. The
pressure in the reservoir may also be maintained above the
predetermined lower threshold through the use of a secondary
dedicated air compressor.
Another embodiment of the present invention relates to a system for
control of a rail vehicle or other vehicle. The system includes a
tractive effort device having a nozzle positioned to direct a flow
of air to a rail, a reservoir fluidly coupled to the tractive
effort device for providing a supply of compressed air to the
tractive effort device, and a control unit electrically coupled to
the tractive effort device and configured to control a flow of
compressed air from the reservoir to the tractive effort device in
dependence upon an available pressure within the reservoir. The
system may also include a continuously variable orifice positioned
between the reservoir and the nozzle of the tractive effort device.
With this configuration, the control unit may be further configured
to control the size of the orifice in dependence upon the pressure
within the reservoir. Moreover, the system may include a first
pathway from the reservoir to the tractive effort device, the first
pathway having a first orifice therein and a first control valve
for selectively controlling a flow of air through the first
orifice, and a second pathway form the reservoir to the tractive
effort device, the second pathway having a second orifice therein
and a second control valve for selectively controlling a flow of
air through the second orifice, the second orifice being smaller
than the first orifice. In this configuration, the control unit may
be electrically coupled to the first and second control valves for
selectively controlling the first and second control valves between
a first state, in which air is permitted to flow therethrough, and
a second state, in which air is prevented from flowing
therethrough. The system may include a first air compressor fluidly
coupled to the reservoir for supplying the reservoir with
compressed air and a second air compressor configured to supply the
reservoir with compressed air in dependence upon the available
pressure within the reservoir.
Yet another embodiment of the present invention relates to a system
for use with a vehicle having a wheel that travels on a surface,
e.g., a rail vehicle having a wheel that travels on a rail. The
system includes a tractive effort system including an air source
for supplying compressed air and a nozzle fluidly coupled to the
air source and configured to direct a flow of compressed air from
the air source to a contact surface of the rail, and a control unit
electrically coupled to the tractive effort system and configured
to control the tractive effort system between an enabled state, in
which compressed air flows from the air source and out of the
nozzle of the tractive effort system, and a disabled state, in
which compressed air is prevented from exiting the nozzle. The
control unit is further configured to control the tractive effort
system from the enabled state to the disabled state in dependence
upon the presence of at least one adverse condition. The at least
one adverse condition may be a geographic location of the rail
vehicle, a curve radius of the rail below a predetermined radius
threshold, the presence of at least one of snow, dust or debris on
a roadbed adjacent the rail, and/or determined ineffectiveness of
tractive effort enhancement.
Yet another embodiment of the present invention relates to a method
for controlling a rail vehicle or other vehicle. The method
includes providing a tractive effort system having a nozzle for
directing the flow of compressed air to the contact surface of a
rail and disabling the tractive effort system when an adverse
condition is detected. The adverse condition may be one of a
geographic location of the rail vehicle, a curve radius of the rail
below a predetermined threshold, a calculated ineffectiveness of
the tractive effort system and a detection of debris on a roadbed
adjacent the rail.
Another embodiment relates to a system for use with a vehicle
having a wheel that travels on a surface, e.g., a rail vehicle
having a wheel that travels on a rail. The system includes an air
source for supplying compressed air, a nozzle fluidly coupled to
the air source and configured to direct a flow of compressed air
from the air source to a contact surface of the rail, a valve
positioned intermediate the air source and the nozzle, the valve
being controllable between a first state in which the compressed
air flows from the air source to the nozzle, and a second, disabled
state in which the compressed air is prevented from flowing to the
nozzle, a controller for controlling the valve between the first
state and the second, disabled state, and an operator interface
electrically coupled to the controller, the operator interface
including a momentary disable switch biased to a position that
controls the valve to the first state and movable against the bias
to control the valve to the second, disabled state. The operator
interface may also include a monostable button actuatable to
selectively toggle the valve between the first state and the
second, disabled state. The controller may be configured to
automatically control the valve to the first state after a
predetermined period of time has elapsed, a certain distance has
been traversed, a certain throttle transition has occurred, a
certain vehicle speed change has occurred and/or a certain tractive
effort level has been attained.
Another embodiment relates to a system for controlling a consist of
vehicles having a plurality of wheels that travel on a surface,
e.g., a consist of rail vehicles having a plurality of wheels that
travel on a rail. The system includes a tractive effort system
on-board a first rail vehicle. The tractive effort system includes
a media reservoir capable of holding a tractive material, a
tractive material nozzle in communication with the media reservoir
and configured to direct a flow of tractive material to a contact
surface of the rail, a compressed air reservoir, and a compressed
air nozzle in communication with the compressed air reservoir and
configured to direct a flow of compressed air to the contact
surface of the rail. The system further includes a control unit
electrically coupled to a first rail vehicle in the consist, the
control unit having a processor and being configured to receive
signals indicative of slippage, individual axle tractive effort,
overall rail vehicle tractive effort and horsepower. The control
unit is further configured to control the tractive effort system to
apply compressed air only to the contact surface of the rail and
monitor at least one of slippage, individual axle tractive effort,
overall rail vehicle tractive effort and horsepower after
application of the compressed air only. The control unit may be
configured to control the tractive effort system to apply tractive
material to the contact surface of the rail as a backup to the
application of compressed air only in dependence upon at least one
of rail vehicle speed and rail vehicle tractive effort. The control
unit may be configured to control the tractive effort system to
apply tractive material to the contact surface of the rail as a
backup to the application of compressed air only in dependence upon
at least one of elapsed time since tractive effort system
activation, distance traversed since tractive effort system
activation, geographical location, operator input and measured or
inferred tractive material reservoir levels.
Another embodiment of the present invention relates to a method for
controlling a rail vehicle or other vehicle having a tractive
effort system. The method includes the steps of enabling the
tractive effort system to apply a blast of air only to the rail,
monitoring one of slip, individual axle tractive effort, overall
tractive effort and horsepower, and enabling the tractive effort
system to apply tractive material to the rail in dependence upon at
least one parameter. The at least one parameter may be a speed of
the rail vehicle, a tractive effort of the rail vehicle, a distance
traveled since the tractive effort system was enabled, and/or
measured or inferred tractive material level.
Another embodiment relates to a method of controlling a rail
vehicle or other vehicle. The method comprises providing a supply
of pressurized air from a reservoir to a tractive effort system of
the rail vehicle, and varying the flow of air to the tractive
effort system to maintain a pressure in the reservoir above a
predetermined lower threshold.
In another embodiment of the method, varying the flow of air
includes selectively controlling a size of an orifice in an air
flow path between the reservoir and a nozzle of the tractive effort
system in dependence upon an available air pressure in the
reservoir. The size of the orifice may be controlled by a
continuously variable orifice valve.
An embodiment relates to a traction system for a vehicle. The
traction system includes a nozzle coupled to an air source and
configured to be selectively aimed toward a determined portion of a
rail surface of a rail. The determined portion is based on a
location of the rail surface between edges of the rail and
proximate to a wheel of the vehicle. The traction system further
includes a conduit, such as a pipe, tube, or hose, configured to
supply pressurized air from the air source to the nozzle, the
nozzle flexibly coupled thereto. The nozzle is configured for the
aim of the nozzle to be controlled to change its aiming direction
in response to a change in curvature of the rail, whereby a stream
of air from the nozzle impacts the determined portion during
movement of the vehicle through the curvature of the rail.
The traction system may further comprise an actuator that is
configured to force the nozzle aiming direction in response to the
change in the curvature of the rail. In an example, the actuator
includes an electromagnet that is coupled to the nozzle. The
electromagnet may be coupled to a voltage source and may be
energized from the voltage source responsive to a signal from an
electronic controller.
The flexible coupling of the nozzle may be provided by a lever
bracket mounted to a frame of the vehicle and mounted to the
conduit, and the traction system may further comprise a resilient
member coupled between the lever bracket and a journal bearing
housing of a lead axle of the vehicle. The lever bracket transforms
lateral movement of the frame relative to the lead axle in a first
direction to lateral movement of the nozzle in a second, opposite
direction, as the curvature of the rail changes.
The traction system may further comprise a sensor that tracks the
rail for curvature, and an actuator configured to actuate the
nozzle to change the aiming direction to maintain the impact of the
air stream on the rail portion during a curve. In examples, the
nozzle is positioned to point at a location in front of a lead
wheel of the vehicle, such that the nozzle is configured to direct
a stream of pressurized air to a point on the rail proximate where
the lead wheel contacts the rail. In examples, the conduit is
coupled to a journal bearing housing of a lead axle of the vehicle.
In an example, the air source is configured to provide air at a
pressure of greater than 620 kPa sufficient to provide the air
stream at a velocity of greater than 23 meters per second
sufficient to increase the tractive effort of the wheel on the
rail.
An embodiment of a system for a vehicle includes a passage
configured to receive pressurized air and coupled to a support of a
lead axle of the vehicle; a nozzle coupled to the passage and
configured to direct the pressurized air to a surface over which
the vehicle is traveling; and a tracking mechanism to adjust one or
more of a position of the nozzle or an angle of the nozzle relative
to the support as a relative direction of travel between the
vehicle and the surface changes.
In an example, the passage may be comprised of a flexible material
and the tracking mechanism may comprise an electromagnet coupled to
the nozzle, the electromagnet configured to be energized when the
surface changes direction in order to adjust one or more of the
position or the angle of the nozzle.
In an example, the tracking mechanism may comprise a lever bracket
coupled to the passage at a first end and to a frame of the vehicle
at a second end. The frame of the vehicle may be configured to move
laterally with respect to the support as the relative direction of
travel between the vehicle and the surface changes, and the lever
bracket is configured to transfer the lateral movement to the
passage in order to adjust one or more of the position or the angle
of the nozzle. In one example, the lever bracket extends
horizontally relative to the frame, and the support comprises a
journal bearing housing. In another example, the lever bracket
extends vertically relative to the frame.
In an embodiment, a method for a vehicle includes directing a
stream of pressurized air via a nozzle to a defined portion of a
surface of a rail over which the vehicle is traveling; and
adjusting an aiming direction of the nozzle based on a curvature of
the surface of the rail.
In an example, adjusting the aiming direction of the nozzle based
on the curvature of the surface of the rail comprises transferring
relative movement between a wheel axle and truck frame of the
vehicle to the nozzle. In an example, adjusting the aiming
direction of the nozzle based on the curvature of the surface of
the rail comprises energizing an electromagnet coupled to the
nozzle. In an example, directing pressurized air onto the rail
comprises directing pressurized air onto the rail responsive to a
detection of wheel slip.
As used herein, an element or step recited in the singular and
proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the invention do not exclude the existence of additional
embodiments that also incorporate the recited features. Moreover,
unless explicitly stated to the contrary, embodiments "comprising,"
"including," or "having" an element or a plurality of elements
having a particular property may include additional such elements
not having that property. The terms "including" and "in which" are
used as the plain-language equivalents of the respective terms
"comprising" and "wherein." Moreover, the terms "first," "second,"
and "third," etc. are used merely as labels, and are not intended
to impose numerical requirements or a particular positional order
on their objects.
The control methods and routines disclosed herein may be stored as
executable instructions in non-transitory memory and may be carried
out by the control system including the controller in combination
with the various sensors, actuators, and other engine hardware. The
specific routines described herein may represent one or more of any
number of processing strategies such as event-driven,
interrupt-driven, multi-tasking, multi-threading, and the like. As
such, various actions, operations, and/or functions illustrated may
be performed in the sequence illustrated, in parallel, or in some
cases omitted. Likewise, the order of processing is not necessarily
required to achieve the features and advantages of the example
embodiments described herein, but is provided for ease of
illustration and description. One or more of the illustrated
actions, operations and/or functions may be repeatedly performed
depending on the particular strategy being used. Further, the
described actions, operations and/or functions may graphically
represent code to be programmed into non-transitory memory of the
computer readable storage medium in the engine control system,
where the described actions are carried out by executing the
instructions in a system including the various engine hardware
components in combination with the electronic controller.
This written description uses examples to disclose the invention,
including the best mode, and also to enable a person of ordinary
skill in the relevant art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
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